Jordan Hall was packed on Monday night for the first mainstage concert of the Boston Early Music Festival, an evening of Mozart’s chamber music. The performers were all accomplished period instrument specialists, but, it’s fair to say, they were not the only draw of the evening. This was also the North American debut of Mozart’s own violin and viola, which arrived in town on Friday, hand-delivered by representatives of the Salzburg Mozarteum Foundation, the owner of both instruments.

Interestingly, both instruments are of good quality, but neither would be considered an example of exquisite 18th-century craftsmanship. The violin, researchers suggest, dates from roughly 1700 and was probably made in Mittenwald, Germany, by a member of the Klotz family of luthiers. The viola’s maker is still unidentified, but the physical object itself tells a story. Its large body was cut back, probably in the early-1800s, suggesting it was at that time still regarded as an instrument for actual musical use, not as a prized relic of music history. Around 100 years later, a silver plate was affixed to the viola’s fingerboard, proudly announcing it as “Mozart’s Viola” and listing the names of its owners dating back to the year of the composer’s death. Somewhere in the intervening century, its aura had been recognized, bestowed, or invented, depending on how one views such things.

Nevertheless, these days the Mozarteum Foundation is interested in having the instruments played more frequently again. For Monday’s concert, the violin and viola were taken up by two veteran performers, Amandine Beyer and Milos Valent, respectively. The program too was thoughtfully assembled to showcase both instruments via two Violin Sonatas (K. 303 and 306), the Duo in G-Major for violin and viola, and the warmly lit “Kegelstatt” Trio for clarinet, viola, and fortepiano (though alas no “Sinfonia Concertante”). Still, even basic details about these instruments remain elusive. Sources tell us Mozart played on the 1786 premiere of the “Kegelstatt” Trio — could it have been on this viola? Did it sound anything like what was heard here? We will never know.

In Valent’s hands the dusky warmth of the instrument’s lower strings came through with particular richness. The viola’s middle and upper registers seemed slightly less open, the sound taking on a somewhat pressed quality on the occasions when Valent tried to project more fully into the depths of Jordan Hall. It was tempting to hear in the viola’s sonic profile a pointed reminder from the composer’s day: that these works were conceived to be played in private homes or chamber-sized spaces.

With Valent joined by clarinettist Eric Hoeprich and fortepianist Kristian Bezuidenhout, the group gave the trio an elegant, soft-spoken reading. The same qualities marked the two violin sonatas, as vibrantly dispatched by Bezuidenhout and Beyer, whose playing throughout the night was lithe and streamlined. The violin’s tone itself was appealingly clear and bright, if somewhat modest for a hall of this size.

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MOZART AT THE BOSTON EARLY MUSIC FESTIVAL

Jordan Hall,

Date of concert:

Monday, June 10

In the Duo, even with the relatively brisk tempos Valent and Beyer chose for all three movements, the performance had a relaxed charm, especially in the tenderly autumnal adagio. For his solo contribution to the program, Bezuidenhout offered Mozart’s Prelude and Fugue (K. 394), placing a superbly controlled technique at the service of music-making notable for its sense of freedom and fantasy.

The sound of the Mozart’s instruments will presumably improve as they are played more often, but, as was clear already from Monday’s demonstration, they provoke the listener to think imaginatively about the particulars of Mozart’s musical world. While receiving the crowd’s applause at one point, Valent held up the viola, giving credit where it was due.

BEMF, too, deserves credit for presenting these instruments on their first trip to the United States. The evening was recorded by WCRB Classical New England, which will broadcast portions of the concert on June 16 at 3 p.m., along with another Mozart performance on these same instruments by violinist Daniel Stepner and violist Anne Black. The violin and viola will also be on display June 12 from 10 a.m. to 1 p.m., at the BEMF exhibition at the Revere Hotel in Boston.

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